1. Field of the Invention
The invention relates to a process for automatically controlling the signal-to-noise ratio in noisy sound recordings.
2. Description of Related Art
It is known how to automatically reduce the background and/or modulation noises in historical and current-day recordings by controlling the signal-to-noise ratio of noisy sound recordings. It is also known that, with certain electronic or data processing procedures, on the one hand, spectral components based on a so-called masking spectrum can be selected, and on the other hand, tonal and noisy peaks can be differentiated based on an analysis of the frequency, amplitude and/or phase characteristic (see Deutsch Eckel Noll (1992) and Brandenburg/Johnson (1990) or McAulay/Quatieri (1986) in the appended bibliography). Once tonal and noisy peaks have been differentiated, then, the amplitude of the noisy peaks can be lowered relative to the amplitudes of the tonal peaks, thus, to improve the signal-to-noise ratio. Here, it is known to work with lowering of the amplitude by a basically constant amount, e.g., -10 dB. Further, it is known to divide the total band of audible frequencies into numerous partial bands and to lower each partial band individually, but always, again, by a constant amount in each case (equalizer principle).